Sealing device for vane-type rotating machine

ABSTRACT

A vane-type rotary machine is shown having vanes concentrically supported in a cylindrical chamber and contacting the inside of this housing. Seals are provided to prevent the leakage of fluid from the chamber around said vanes. These seals include shoes for preventing leakage along the ends of the vanes, the shoes being formed with inwardly extending projections to increase their contact area with the relatively sliding vanes to increase the life of the vanes.

United States Patent [1 1 Katsutoshi et a1.

[ Oct. 21, 1975 SEALING DEVICE FOR VANE-TYPE ROTATING MACHINE [75] Inventors: Kitagawa Katsutoshi, Seto; Adachi Yoshiaki; Dono Katsuyasu, both of Toyota, all of Japan [73] Assignee: Toyota. Jidosha Kogyo Kabushiki Kaisha, Toyota, Japan 22 Filed: Nov. 5, 1974 21 Appl. No.: 521,059

[30] Foreign Application Priority Data Apr. 16, 1974 Japan 49-41822 [52] US. Cl. 418/137 [51] Int. Cl? F01C 19/08; F04C 27/00 [58] Field of Search 418/137, 138

[56] References Cited UNITED STATES PATENTS 3,401,872 9/1968 Adsit 418/138 3,790,317 2/1974 Hyde et al. 418/137 Primary Examiner-William L. Freeh Assistant Examine'rLeonard Smith Attorney, Agent, or Firm-Finnegan, Henderson, Farabow & Garrett [57] I ABSTRACT A vane-type rotary machine is shown having vanes concentrically supported in a cylindrical chamber and contacting the inside of this housing. Seals are provided to prevent the leakage of fluid from the chamber around said vanes. These seals include shoes for preventing leakage along the ends of the vanes, the shoes being formed with inwardly extending projections to increase their contact area with the relatively sliding vanes to increase the life of the vanes.

1 Claim, 3 Drawing Figures US. Patent Oct. 21, 1975 SEALING DEVICE FOR VANE-TYPE ROTATING MACHINE BACKGROUND The so-called vane-type rotary machines are well known as shown in the patent to Adsit, US. Pat. No. 3,401 ,872; issued Sept. 17,- 1968; which machine comprises a housing, vanes rotating in contact with the inside of the housing, and a rotor provided in said housing and rotating with said vanes. This type of vane-type rotating machine is suggested for use as an air pump for supplying secondary air to the exhaust gas system of an internal combustion engine to provide additional oxygen for completing the combustion of burnable constituents in the exhaust gases or the combustion products issuing from an automobile engine, for example.

As seen in US. Pat. No. 3,401,872, there is provided in a cylindrical housing 22 vanes 42 that are mounted to rotate concentrically about the axis of the housing in contact with the walls defining the inside of the housing. The housing is also provided with a cylindrical rotor 23 that drives the vanes. The rotor is mounted to rotate about an axis that is eccentric with respect to the axis of the housing and the rotor cooperates with said vanes that slide relative to the rotor through slots 43 formed in the rotor. The ends and tips of the vanes engage the inside walls of the housing and as they are driven around due to the eccentric position of the rator, air is pumped as more fully discussed in the aforementioned patent. For this purpose, the slots in the rotor must be large enough to permit the vanes to swing or oscillate therein as the pump is driven and sealing means must be provided to prevent compressed air from flowing from the housing back around the vanes to the hollow inside space within the rotor.

To prevent this communication or back flow of compressed air into such space, the vanes have wedgeshaped bearing shoe strips 76 and 78 resiliently pressed against their front and rear faces in such a manner as to prevent air from flowing along these faces and through the slots. Suitable retainers 70 are fixed on the inside periphery of the rotor to hold the seals 76 and 78 in place. The vanes are also sealed on their ends to complete the seal around the slot and for this purpose, a pair of arcuate carbon shoe strips 84 are interposed between the vanes ends and the strips 82 to prevent leaks through the slots at the ends of the vanes. The

several arcuate shoe strips provided for sealing the ends BRIEF DESCRIPTION OF THIS INVENTION This invention is concerned with providing an improved sealing means for the ends of the vanes in a rotary machine like that described above. In following this invention, arcuate shoe strips are provided for cooperating with the opposite endsof each of the vanes. The shoe strips here disclosed include additional bearing surfaces for engaging against't he ends of the vanes. With this structure, the force applied to press the shoe strips against the vanes can be increased to make the seals most effective, without increasing the unit pressure of the seals against the vanes, in a manner to produce undue wear.

Of the drawings:

FIG. 1 is a sectional elevation showing the housing, rotor, and seal assembly, the left-hand side being a representation showing the structure with wedge-shaped seals 7 removed from the vane on the left-hand side;

FIG. 2 is a sectional view, partly broken away, taken on line 2-2 of FIG. 1; and

FIG. 3 is a detail sectional view taken on line 3--3 of FIG. 2, showing the sliding or rubbing action of the end of a vane against a shoe strip or seal forming the subject of this invention.

DETAILED DESCRIPTION Referring to the drawings, the housing 1 has a pair of vanes 2 rotating therein in contact with the inside walls of the housing, and a rotor 3 is provided for driving said vanes. This type of known rotary machine is used for pumping air as above explained.

The vanes 2 rotate concentrically within the circular chamber of the housing in contact with the walls forming the interior periphery of the housing. The rotor 3 is mounted eccentrically to the axis of the chamber, the rotor being driven to drive the vanes. As the rotor rotates about its axis displaced from the central axis of the circular chamber in the housing about which the vanes rotate, the vanes are caused to slide in slots 4 in the periphery of the rotor. The rotor is driven in the direction of the arrow in FIG. 1 and air is let into the circular chamber through an inlet (not shown) in the lefthand side of chamber 5 as shown in FIG. 1. The vanes are driven around in chamber 5 in the housing and the air in front of each of the vanes is compressed somewhat as it flows to an outlet at the lower right hand of FIG. 1 (not shown). The chamber 5 would communicate through slots 4 with the inside space in hollow chamber 6 inside the rotor unless sealing means are provided and thus wedge-shaped seals 7 are shown. The seals 7 are slidingly carried on the inside periphery of rotor 3 and engage against the front and back sides of vanes 2. The seals 7 are urged against the oppositely disposed faces of the vanes by springs 8. The seals and springs are held by retainers 9 fixed to the inner periphery of rotor 3. The seals 7 prevent air from flowing over the front and rear faces of the vanes from chamber 5 into chamber 6.

As shown in FIG. 1, retainers 9 that are fixed to the inner periphery of rotor 3 adjacent slots 4 are oppositely disposed on the front and rear sides of vanes 2 and extend from one end 10 to the other end 10 of the vanes. The retainers are spaced from the front and rear sides of the vanes to leave a space h between their edges of such a size that permits the vanes 2 to swing therein. Side shoes or seals 12 are also carried in retainers 9 for sealing both the ends of the vanes with respect to the wall 14 forming a part of the inside periphery of rotor 3 to prevent air from flowing from chamber 5 into the space 6 inside rotor 3.

The essence of this invention is concerned with leaving said space h for receiving a projecting portion 13 formed integral with each of the side shoes 12, and allowing said projecting portions 13 to protrude into the spaces 11 between said retainers 9. As illustrated in FIG.

3, the pressure receiving area of the side shoe 12 and extension 13, according to this invention, is greater than that of the conventional arcuate sealing shoe by the area of the projected portion 13. This positive expansion of the bearing area of the side shoe seal means against the vanes results in a large increase in durability and life of the end seals.

The seals 7 and side shoe seals 12 may be made of any conventional material such as graphite or a suitable resin bonded element that functions to provide a relatively friction free engagement between the moving parts while maintaining a proper seal.

As described above, this invention makes it possible to provide a side shoe for sealing the ends of the vanes having increased durability without necessitating any alteration on other parts of the conventional air pump. Therefore, this invention brings about many remarkable results, including an increase in reliability, life and durability of machines.

While a specific embodiment related with the air pump has been shown and described, this invention should not be limited thereto, but it is broadly directed to the vane-type rotating machines in general; that is, liquid pumps, prime movers, and the like. It is possible that modifications of this invention may occur to those skilled in the art that will fall within the scope of thefollowing claim.

What is claimed is:

1. A sealing device for the ends of the vanes of a vane-type rotary machine having a housing enclosing a circular chamber in which the vanes rotate and having a surface against which the'vanes are sealed; a hollow cylindrical rotor eccentrically mounted in the circular chamber in the housing for driving the vanes, the rotor ements engaging between the ends of the vanes and the inside periphery of the rotorto prevent air flow along l the ends of the vanes, each of said shoes having an inwardly projecting portion covering an extended portion of an end of each of said vanes respectively; and re tainer means carried on the inside periphery of said rotor for holding said side shoe sealing elements against the ends of said vanes with the projecting portion in alignment with and bearing on the ends of the vanes to provide a large contact area between said side shoes and the ends of said vanes. 

1. A sealing device for the ends of the vanes of a vane-type rotary machine having a housing enclosing a circular chamber in which the vanes rotate and having a surface against which the vanes are sealed; a hollow cylindrical rotor eccentrically mounted in the circular chamber in the housing for driving the vanes, the rotor having slots in its periphery forming openings in which the vanes are disposed; sealing means for sealing the front and rear faces of the vanes with respect to the openings; side sealing means for sealing the ends of the vanes with respect to the inside periphery of the rotor, said side sealing means comprising side shoe sealing elements engaging between the ends of the vanes and the inside periphery of the rotor to prevent air flow along the ends of the vanes, each of said shoes having an inwardly projecting portion covering an extended portion of an end of each of said vanes respectively; and retainer means carried on the inside periphery of said rotor for holding said side shoe sealing elements against the ends of said vanes with the projecting portion in alignment with and bearing on the ends of the vanes to provide a large contact area between said side shoes and the ends of said vanes. 